Rabble for mechanical roasting-furnaces.



W. HOMMEL.

RABBLE FOR MECHANICAL ROASTING FURNACES.

APPLICATION FILED AUG.23.1916.

1,2O,51 3. Patented Mar. 27, 1917.

M 2 SHEETS-SHEET I W. HOIVIMEL.

RABBLE FOR MECHANiCAL ROASTING FURNACES.

APPLICATION FILED AUG.23, 1916.

1 ,2ZQ5 1 3 Patented Mar. 27, 1917.

2 SHEETS-SHEET 2.

nnrann sra'rns rarnnr onrron WOLDEMAR HOMIVIELQOF ZURICH, SWITZERLAND.

RABBLE FOR MECHANICAL ROASTING-FURNACES.

Specification of Letters Patent.

Patented Mar. 27, 1917.

Application filed August 23, 1916. Serial No. 116,568.

of which the following is a specification.

My invention relates to rabbles for mechanical roasting furnaces in which the rabbleor scraper-blades are moved to and fro at right angles to the direction of travel of the ore or other material to be roasted.

Roasting furnaces of this kind heretofore employed gave rise to the inconvenience of the ore or other material to be roasted accumulating unnecessarily along both longitudinal Walls of the furnace where it remained and was therefore temporarily lost for the roasting effect.

The object of my present invention is to eliminate this undesirable feature by making the blades of the rabble of a particular shape, described hereinafter. As is known the working faces of scraper blades which cause the ore to travel along the hearth of the furnace are set perpendicular to the hearth-level or bottom and obliquely to the traveling direction of the rabble. Two series of such blades are necessary. They are working alternately in such a manner that by every movement of the rabbles in the one or the other direction the working faces of the other series conveying it in the opposite direction across the hearth, the ore is brought forward one step along the hearth.

Now, it is not to be avoided that with each stroke the blades of the non operative or idle series will push aside a certain small amount of ore and that this ore will accumulate along the longitudinal walls of the hearth.

A further object of my invention is to avoid such undesirable accumulations of ore by giving the non operative or outward part of the blades a plow-like shape viz. an inclined face extending from the top of the working face downward to a horizontal, preferably sharp edge which engages and travels over the hearth level. This arrangement causes the scraper blades of the idle series to penetrate into the under layersof the ore accumulated at the side of the hearth in such a way, that a part of this ore slides over the upwardly extending faces of the blades and drops toward the middle of the hearth. But even with blades of such a shape small accumulations of ore cannot completely be avoided, as still small quan tities of ore collect in the spaces between two adjacent blades.

Another object of my invention is to avoid such accumulations by bridging the spaces between the blades by means of suitable stays which also have inclined faces and remove thereby the top of the small ore heaps or accumulations formed between the blades.

In the accompanying drawings:

Figure l is a side view of the rabble ac- I cording to my invention. Fig. 2 is a plan view of this rabble. Fig. 3 is a cross-section on the line AB, Fig. 2; Fig. 4 is a perspective view of a scraping blade; Fig. 5 is a section through the blades on the line CD, Fig. 2; Fig. 6 is a view showing the position of the blades when conveying the ore to ward the left; and Fig. 7 is a sectional view of the furnace showing the way of working" of the rabble according to my invention.

Referring to the drawings, a is a hollow beam which is reciprocated as shown in Fig. 7 in a known manner transversely with regard to the longitudinal axis of the furnace by means of a rod Z2 guided in the furnace wall, Fig. 7 Fixed to the beam at are two groups or series I and II, each containing" a number of blades 0 each of which blades has a working face (2 perpendicular to the hearth level, as shown in Fig. 3. The blades of each series are arranged in an image-like or mirrored and a staggered way with regard. to

the blades of the-other series so that when the rabble moves to and fro, the whole of the ore to be roasted is stirred up and is alternately moved forward longitudinally of the furnace by the working faces (Z in a known way so that when the rabble moves in the direction of the arrow 1 Figs. 2 and 7, the ore is conveyed by the blade series I, the blade series II producing the same effect when the rabble moves in the dirccti on of the arrow 2.

I11 order to cause the ore conveyed by one of the blade series to be completely caught by the other blade series these series of blades are not transposed to the extent of a full blade-width or interval, but they are so placed that the edges of the blades of each series reach into the working radius of the blades of the other series.

The faces 6 adjoining the inclined perpendicular working faces (Z of each blade are sloping downwardly and outwardly, preferably as shown in Fig. 3, so that they form cutter-like sharp edges 9 with the ground-faces or bases of the blades. By

. these down slopingouter faces the blades obtain a wedge-like shape.

The way of working of the so shaped blades is clearly shown in Fig. 7. \Vhen the rabble moves in the direction of the arrow 1 from the left to the right transversely over the hearth level, merely the working faces d of the blades of series I shown in dotted lines in Fig. 7, perform the convoyance of the ore longitudinally of the fur nace, whereas the blades of series II take no part in this conveyance. The blades of series II would rather move the ore placed in front thereof along if they were provided with a face perpendicular to the hearthlevel and parallel to the longitudinal axis of the furnace and they would cause this ore to be conveyed toward the right longitudinal wall of the furnace, where it would accumulate. But as the blades of series II are provided with sharp edges sliding over the hearth level, adjacent to which is the face 6, extending upwardly, the ore will now slide over these faces 6 toward the middle of the hearth and drop over the top edge of the blades, as shown by the arrows on the right of Fig. 7 so that any objectionable accumulations of ore along the longitudinal walls of the hearth which would disturb the working of the furnace, are eliminated.

When the rabble moves in the direction of the arrow 2, the blades of series II con- Vey the ore longitudinally of the hearth, whereas now the edges 9 and the faces 6 of the blades of series I penetrate under this ore and cause it to fall toward the middle of the hearth as already described.

In order to avoid accumulations of ore between the blades alongside the longitudinal furnace walls the blades 0 are connected with each other on their outer parts by webs 0r stays '5 bridging the space between each two blades 0. The upper side or face of each stay passes directly into the adjacent blade faces 6 and has an outward down-slope similarly to the faces 6.

The bridge-like stays i being wedgeshaped, enter into the ore, on the left similarly to the blades of the rabble, as shown in Fig. 7 In doing so, they act as ductors or strippers as they only take off the accumulations above the required layer of ore and push it back toward the middle of the hearth. Therefore the bridges or stones Z which have heretofore been arranged in the G9 doors is ofthe furnace h and having the height of the lateral ore accumulations and which make the surveyance of the furnace very difiicult, can now be made considerably lower, for instance as shown in dotted 65 lines in Fig. 7.

In addition each of the blades 6 has a vertical web an arranged in the direction of the rabble-motion at the side of the downsloping face 6, this web ending outwardly by a cutterlike edge at as shown in Fig. 4. Preferably this cutting edge directly joins the outer cutting edge 9 of the blades. By means of these webs m ending by cutteredges, the blades can more easily penetrate into the ore. They also help by pushing the accumulated ore up the wedge-like surfaces 6 of the blades.

Adjoining the cutter-like outer edge '9 if of each blade and also at the side of. the downsloping wedge-life face a each blade is further provided with a small perpendicular face 0. This inclined face acts as an auxiliary face and is intended to push away particularly along the longitudinal walls of the furnace cavity the ore situated under the bridge-like stays and to feed it toward the working faces 6 proper.

The blades and consequently also their working faces must be arranged as shown in Fig. 2 or Fig. 6, according to whether the ore is to be conveyed to the right or to the left. This arrangement of the blades is necessary when the roasting furnace has two hearths lying one above the other and when the rabbles of both hearths are moved together.

The blades 0 may form parts of the beam (4 or be rigidly fixed to it. But preferably the blades are arranged in such a manner that they can be removed from the beam each one separately or in groups, in order to be readily inspected or replaced and in order to allow of varying the dimensions of the hollow space. There can be any desired number of blades and they can be fixed on the rabble in any desired way. The bridgelike connecting stays i can also be dispensed with as well as the auxiliary working faces 0.

The outwardly downslopingfaces of the blades need not necessarily reach down to the basis of these blades; under certain conditions it will also do if they reach down approximately to one half of the height or thickness of the ore-layer on the hearth level.

What I claim as new and desire to secure by Letters Patent is:

1. In a rabble for a mechanical roasting furnace having two groups or series of scraper blades arranged alternately or staggered relatively to each other and provided with inclined working faces arranged per pendicularly to the hearth level, on each of the blades an outwardly downsloping facee adjoining the inclined working face acting 7 like a plow-blade.

2. In a rabble for a mechanical roasting furnace having, groups or series of scraper blades arranged alternately or staggered 130 relatively to each other, provided with inclined working faces arranged perpendicularly to the hearth level and outwardly downsloping faces on each of the blades adjoining the inclined working face acting like a plow-blade, an outwardly downsloping face e forming a cutter-like sharp edge g with the basis of the respective blade.

3. In a rabble for a mechanical roasting furnace having groups or series of scraper blades arranged alternately or staggered relatively to each other, provided with inclined working faces arranged perpendicularly to the hearth level and outwardly downsloping faces on each of the blades adjoining the inclined working face acting like a plow-blade, bridge-like stays 2' coI1- necting the blades with each other.

4. In a rabble for a mechanical roasting furnace having groups or series of scraper blades arranged alternately or staggered relatively to each other, provided with inclined working faces arranged perpendicularly to the hearth level and outwardly Copies of this patent may be obtained for five cents each, by addressing the downsloping faces on each of the blades adjoining the inclined working face acting like a plow-blade, a vertical web m adjoin: ing the cutter-like outer face of each blade and also ending like a cutter.

5. In a rabble for a mechanical roasting furnace having groups or series of scraper blades arranged alternately or staggered relatively to each other, provided with in,- clined working faces arranged perpendicularly to the hearth level and outwardly downsloping faces on each of the blades adjoining the inclined working face acting like a plow-blade, a small inclined perpendicular face 0 adjoining the cutter-like outer edge 9 of the blade laterally of the downsloping face.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

WOLDEMAR HOMMEL.

Witnesses:

HENRY HASPER, ARTHUR SOHROEDER.

Commissioner of Patents,

Washington, D. G. 

